Initial rotor position detections for an integrated PM synchronous motor drive

By integrating the motor, the power converter and the control circuits of electrical drives into one casing, several advantages are obtained. The drive becomes compact, the amount of wiring is significantly reduced and the control of the inverter and the motor can be designed to better utilize their respective characteristics. The paper presents an integrated PM synchronous motor drive (IPMSM) using complete digital control. The control includes a simple sensorless estimation of the rotor position both at standstill and under rotation. The algorithm for the initial rotor position detection is based on the saliency of the rotor at no load and it provides both the location as well as the direction of the magnetization. Under rotation, the rotor position is estimated by a predictor-corrector based observer. The integrated concept makes it simple to include accurate values of the machine parameters.